lxc-usernsexec(1) - Run a task as root in a new user namespace.

  • lxc-usernsexec(1)					     lxc-usernsexec(1)
           lxc-usernsexec - Run a task as root in a new user namespace.
    [-m uid-map] {-- command}
           lxc-usernsexec can be used to run a task as root in a new user
           -m uid-map
    	      The uid map to use in the user namespace. Each map consists of
    	      four colon-separate values. First a character 'u', 'g' or 'b' to
    	      specify whether this map pertains to user ids, group ids, or
    	      both; next the first userid in the user namespace; next the
    	      first userid as seen on the host; and finally the number of ids
    	      to be mapped.
    	      More than one map can be specified. If no map is specified, then
    	      by default the full uid and gid ranges granted by /etc/subuid
    	      and /etc/subgid will be mapped to the uids and gids starting at
    	      0 in the container.
    	      Note that lxc-usernsexec always tries to setuid and setgid to 0
    	      in the namespace. Therefore uid 0 in the namespace must be
           To spawn a shell with the full allotted subuids mapped into the
           container, use
           To run a different shell than /bin/sh, use
    	      lxc-usernsexec -- /bin/bash
           If your user id is 1000, root in a container is mapped to 190000, and
           you wish to chown a file you own to root in the container, you can use:
    	      lxc-usernsexec -m b:0:1000:1 -m b:1:190000:1 -- /bin/chown 1:1 $file
           This maps your userid to root in the user namespace, and 190000 to uid
           1.  Since root in the user namespace is privileged over all userids
           mapped into the namespace, you are allowed to change the file
           ownership, which you could not do on the host using a simple chown.
           lxc(7), lxc-create(1), lxc-copy(1), lxc-destroy(1), lxc-start(1), lxc-
           stop(1), lxc-execute(1), lxc-console(1), lxc-monitor(1), lxc-wait(1),
           lxc-cgroup(1), lxc-ls(1), lxc-info(1), lxc-freeze(1), lxc-unfreeze(1),
           lxc-attach(1), lxc.conf(5)
           Serge Hallyn <serge.hallyn@ubuntu.com>
    				  2018-06-01		     lxc-usernsexec(1)

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